The animal with the largest brain is the sperm whale. Its brain weighs approximately 17 pounds and can grow to be nearly 500 cubic inches.

Although the sperm whale has the largest brain, the species is not considered to be the most intelligent creature. Intelligence correlates more with the components of the brain and the ratio of brain weight to body weight rather the sheer size of the brain alone. For example, the human brain weighs in at around 3 pounds, but it takes up more weight in the body proportionally than the brains in the bodies of other animals.